The invention relates to the optical transmission and reception of digital data and, more particularly, to a system and method for providing such in a mobile user environment.
Within modem data systems local area networks (xe2x80x9cLANsxe2x80x9d) which facilitate user-to-user or user-to-computer communications are common place. Typically systems comprise a central network connected by either dedicated connection lines or a general purpose telecommunication system to various user terminals. These networks employ various data protocols that allow information to be exchanged among the user terminals. While existing LAN architectures and protocols allow users a good deal of flexibility, users are still limited in mobility by the connection (be it wire or optical fiber) which tethers them to the network server. In addition, these xe2x80x9chard-wirexe2x80x9d connections also detract from the ease with which a given LAN can be reconfigured. If a terminal is to be added or relocated, additional connection lines must be runxe2x80x94Usually a rather time consuming and cost intensive operation.
Previous systems have attempted to solve this mobility problem by providing either a radio and/or infrared optical link between mobile user terminals and LANs. Typically, data communications over the radio-based systems were subject to electromagnetic interference, and previous infrared optical systems have lacked an effective central control to avoid and mediate data collisions. In particular, present infrared-based systems have typically had nodes xe2x80x9clisten-while-talkingxe2x80x9d so that transmissions could be terminated if a data collision occurred. This permits the system to recover quickly after a collision occurs, but does nothing to avoid collisions.
The present invention overcomes the deficiencies of prior optical data communication systems for LANs by employing a centralized controller in conjunction with a robust protocol and contention scheme. This combination enables the invention to facilitate the optical transport of data between a number of nodes without collision. The invention is particularly suited to optical transmissions between several mobile nodes and one or more stationary network nodes, allowing communication with the network as the mobile nodes roam from the vicinity of one network node to the next.